Network Administration and Security (CSCT6110)

DIPET 2 in ICT - ICTT

Semester: First Semester

Level: 500

Year: 2018

Answers (200 )
1)
2)
3)
Consider the figure below, with three links, each with the specified transmission rate and link
length.
REPUBLIC OF CAMEROON THE UNIVERSITY OF BAMENDA
Peace-
Work
School:
Course Code:
Lecturer:
Date:
24/01/2019
INSTRUCTION:
Exercise 1
1)
Define the following words and expression
protocol.
2)
State three advantages of using optical fiber over other wire media
3)
With suitable example, E
sniffing, IP spoofing
Exercise 2
1)
2)
3)
Consider the figure below, with three links, each with the specified transmission rate and link
length.
REPUBLIC OF CAMEROON THE UNIVERSITY OF BAMENDA
Work
-
Fatherland P.O. Box 39 Bambili
School:
H.T.T.T.C
Course Code:
CST6110
Lecturer:
Mr.
DJIMELI T. CHARLY
24/01/2019
INSTRUCTION:
Exercise 1
:
Introduction to networking system
Define the following words and expression
State three advantages of using optical fiber over other wire media
With suitable example, E
sniffing, IP spoofing
.
Exercise 2
:
Application and transport layer
List the two key elements
Draw the architecture of an electronic mail system, by specifying the protocol used at each
level of communication
What is congestion? Describe how it is manifested in
Exercise 3
:
Computing end
Consider the figure below, with three links, each with the specified transmission rate and link
Find the end
-to-
end delay (including the transmission delays and propagation delays on each
of the three links, but ignoring queueing delays and processing delays) from when the left host
begins transmitting the first bit of a packet to the time when the l
REPUBLIC OF CAMEROON THE UNIVERSITY OF BAMENDA
Fatherland P.O. Box 39 Bambili
Department:
CST6110
DJIMELI T. CHARLY
Time:
Answer to all the questions inside your booklet
Introduction to networking system
Define the following words and expression
State three advantages of using optical fiber over other wire media
With suitable example, E
xplain
Application and transport layer
List the two key elements
necessary to identify a network process
Draw the architecture of an electronic mail system, by specifying the protocol used at each
level of communication
What is congestion? Describe how it is manifested in
Computing end
-
end delay (transmission and propagation delay)
Consider the figure below, with three links, each with the specified transmission rate and link
end delay (including the transmission delays and propagation delays on each
of the three links, but ignoring queueing delays and processing delays) from when the left host
begins transmitting the first bit of a packet to the time when the l
REPUBLIC OF CAMEROON THE UNIVERSITY OF BAMENDA
Fatherland P.O. Box 39 Bambili
First Semester Examinations
Department:
Computer Science
Course Title:
DJIMELI T. CHARLY
Time:
1 hr 30
Answer to all the questions inside your booklet
Introduction to networking system
Define the following words and expression
State three advantages of using optical fiber over other wire media
xplain
the
following network threat:
Application and transport layer
necessary to identify a network process
Draw the architecture of an electronic mail system, by specifying the protocol used at each
What is congestion? Describe how it is manifested in
end delay (transmission and propagation delay)
Consider the figure below, with three links, each with the specified transmission rate and link
end delay (including the transmission delays and propagation delays on each
of the three links, but ignoring queueing delays and processing delays) from when the left host
begins transmitting the first bit of a packet to the time when the l
REPUBLIC OF CAMEROON THE UNIVERSITY OF BAMENDA
Fatherland P.O. Box 39 Bambili
First Semester Examinations
Computer Science
Course Title:
Start Time:
Answer to all the questions inside your booklet
Introduction to networking system
Define the following words and expression
:
Network administration
State three advantages of using optical fiber over other wire media
following network threat:
Application and transport layer
necessary to identify a network process
Draw the architecture of an electronic mail system, by specifying the protocol used at each
What is congestion? Describe how it is manifested in
end delay (transmission and propagation delay)
Consider the figure below, with three links, each with the specified transmission rate and link
end delay (including the transmission delays and propagation delays on each
of the three links, but ignoring queueing delays and processing delays) from when the left host
begins transmitting the first bit of a packet to the time when the l
REPUBLIC OF CAMEROON THE UNIVERSITY OF BAMENDA
Fatherland P.O. Box 39 Bambili
First Semester Examinations
Computer Science
Course Title:
Network administration and security
Start Time:
10:00 AM
Answer to all the questions inside your booklet
Network administration
State three advantages of using optical fiber over other wire media
following network threat:
Denial of
necessary to identify a network process
Draw the architecture of an electronic mail system, by specifying the protocol used at each
What is congestion? Describe how it is manifested in
a
network.
end delay (transmission and propagation delay)
Consider the figure below, with three links, each with the specified transmission rate and link
end delay (including the transmission delays and propagation delays on each
of the three links, but ignoring queueing delays and processing delays) from when the left host
begins transmitting the first bit of a packet to the time when the l
REPUBLIC OF CAMEROON THE UNIVERSITY OF BAMENDA
Fatherland P.O. Box 39 Bambili
Option:
Network administration and security
Credit Value:
End Time:
Answer to all the questions inside your booklet
Network administration
,
Network security
(
State three advantages of using optical fiber over other wire media
Denial of
Service (
(5 Marks)
necessary to identify a network process
Draw the architecture of an electronic mail system, by specifying the protocol used at each
network.
.
end delay (transmission and propagation delay)
Consider the figure below, with three links, each with the specified transmission rate and link
end delay (including the transmission delays and propagation delays on each
of the three links, but ignoring queueing delays and processing delays) from when the left host
begins transmitting the first bit of a packet to the time when the l
ast bit of that packet is
REPUBLIC OF CAMEROON THE UNIVERSITY OF BAMENDA
Fatherland P.O. Box 39 Bambili
Option:
ICT
Network administration and security
Credit Value:
End Time:
11:30 AM
15
Marks
Network security
(
5 Marks)
(5
Marks
Service (
DoS), paquet
(5 Marks)
14
Marks
(2x2=4
Marks)
Draw the architecture of an electronic mail system, by specifying the protocol used at each
(
5
(
5
end delay (transmission and propagation delay)
Consider the figure below, with three links, each with the specified transmission rate and link
end delay (including the transmission delays and propagation delays on each
of the three links, but ignoring queueing delays and processing delays) from when the left host
ast bit of that packet is
REPUBLIC OF CAMEROON THE UNIVERSITY OF BAMENDA
Network administration and security
Credit Value:
11:30 AM
Marks
Network security
Marks
)
DoS), paquet
Marks
Marks)
Draw the architecture of an electronic mail system, by specifying the protocol used at each
5
Marks)
5
Marks)
Consider the figure below, with three links, each with the specified transmission rate and link
end delay (including the transmission delays and propagation delays on each
of the three links, but ignoring queueing delays and processing delays) from when the left host
ast bit of that packet is
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received at the server at the right. The speed of light propagation delay on each link is
3x10**8 m/sec. Note that the transmission rates are in Mbps and the link distances are in Km.
Assume a packet length of 4000 bits. Give your answer in milliseconds.
Exercise4: DNS and HTTP delays 26 Marks
Suppose within your Web browser you click on a link to obtain a Web page. The IP address
for the associated URL is not cached in your local host, so a DNS lookup is necessary to
obtain the IP address. Suppose that four DNS servers are visited before your host receives the
IP address from DNS. The first DNS server visited is the local DNS cache, with an RTT delay
of RTT
0
= 5 msecs. The second, third and fourth DNS servers contacted have RTTs of 50, 14,
and 46 msecs, respectively. Initially, let's suppose that the Web page associated with the link
contains exactly one object, consisting of a small amount of HTML text. Suppose the RTT
between the local host and the Web server containing the object is RTT
HTTP
= 16 msecs.
1. Assuming zero transmission time for the HTML object, how much time elapses from when
the client clicks on the link until the client receives the object?
2. Now suppose the HTML object references 2 very small objects on the same web server.
Neglecting transmission times, how much time elapses from when the client clicks on the
link until the base object and all 2 additional objects are received from web server at the
client, assuming non-persistent HTTP and no parallel TCP connections?
3. Repeat 2. Above but assume that the client is configured to support a maximum of 5
parallel TCP connections, with non-persistent HTTP.
4. Repeat 2. Above but assume that the client is configured to support a maximum of 5
parallel TCP connections, with persistent HTTP.
5. What do you notice about the overall delays (taking into account both DNS and HTTP
delays) that you computed in cases 2., 3. and 4. above?
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